The present invention relates in general to active bolsters for passenger vehicles, and, more specifically, to an active bolster and mounting system incorporated in a side door of a vehicle.
In order to reduce loads applied to an occupant from impact during a vehicle crash, active bolster systems are sometimes installed within a vehicle interior. They may be located in an instrument panel or glove box door to protect the knees or in a door panel, window pillar, or seat structures to protect against side impacts. A typical active bolster is formed from a plastic bladder shaped into a bellows or pleated configuration on one surface. Upon the occurrence of a crash event of sufficient magnitude, an inflator is activated to inflate the bolster and expand the bladder to create an impact cushion.
An active bolster assembly must be mounted in a way that ensures a proper orientation and support during a deployment (i.e., expansion) toward the occupant. The mounting should ensure that it deploys without any obstructions or misalignments that could degrade its trajectory or performance, and should not produce forces that would dislodge the trim panel from its own mounting to an underlying structural element. Moreover, the appearance of the bolster itself and its fit within surrounding trim elements must meet craftsmanship specifications such as gap size, gap consistency, and flushness.
A bolster assembly is typically mounted to an underlying fixed structural element of the vehicle in order to support the bolster against expansion and to receive the forces applied against the bolster during impact with an occupant. In the case of an active side impact system, the bolster may be mounted to a door frame. A door trim substrate or cover panel is also mounted to the door frame to provide the interior surface of the door. The trim substrate panel includes an opening for receiving the bolster, and the bolster has an outer surface with a desired color and texture to match the trim panel.
An active bolster assembly typically includes a rigid backplate or housing member containing the bladder that acts as a reaction surface during expansion of the bladder. The backplate for a door side bolster may be attached to the door frame as is typically done or may be independently supported by the trim panel itself as disclosed in copending application U.S. Ser. No. 13/251,652, filed Oct. 3, 2011, entitled “Active Bolster with Integrated Tear Seam.” The backplate takes up space within the interior of the door, where available space can already be severely limited by styling surfaces or the presence of other components. It would be desirable to eliminate the backplate to make more efficient use of the interior space of the door and to reduce cost and weight of an active bolster assembly, while maintaining good fit and finish of the bolster.